also use a heat gun after sanding
,with acetone, the repair area.
pvc will not bond if there is any humidity at all.
,best trim patch to butt up to raised area,then cover with 2nd patch for larger punctures,though with a good bond 2cm to the edge of the patch for smaller leaks
follow instructions very carefull for the pvc glue you will only have about 2minutes to work with it,so dont mix too much.
would use heat gun again briefly on the glued sides before applying the patch.
apply pressure to repair for 24 hours if possible.
and do not inflate for 24hours.
with high humidity you definitely need to use a heat gun to dry out the water
molecules on the surface.